Vegetative Organ Anatomy and Pollen Morphology of Endemic Prometheum chrysanthum subsp. uludagense Kaynak, Yılmaz & Daşkın (Crassulaceae)

Prometheum (A.Berger) H.Ohba is a small genus in Crassulaceae and represented by seven species, two subspecies, and two varieties in Türkiye. One of these, Prometheum chrysanthum subsp. uludagense Kaynak, Yılmaz & Daşkın is an endemic taxon that has a very limited distribution. It grows in rocky habitats, extreme climate conditions and has a succulent character. The purpose of this study is to provide a complete presentation of the anatomical features and pollen morphology of P. chrysanthum subsp. uludagense. The root, stem, and leaf cross-sections were taken manually and investigated by light microscopy. The root revealed a secondary structure. Xylem components were centralized in the pith and surrounded by phloem. The shape of the stem was rounded, and it had a thick cuticle periphery. Characteristic multicellular biseriate glandular trichomes covered the stem and leaf surfaces. The mesophyll layer of the leaf was undifferentiated, and vascular bundles were surrounded by sclerenchymatous cells. The pollen grains were monad, radially symmetric, oblate-spheroidal in shape and had a tricolporate aperture type. The tectum surface had no surface sculpture; the ornamentation was psilate. The findings showed that pollen morphology characteristics such as ornamentation, shape, and outline in polar view were taxonomically important.